1. Field of the Invention
The invention relates to evaporative coolers, and specifically relates to a drainage arrangement for evaporative coolers.
2. Discussion of Prior Art
An evaporative cooler may be useful where high ambient temperatures and low relative humidity are common. Within an evaporative cooler, water is added to inlet air. Part of the water evaporates absorbing latent heat from the air. As a result, the air, which gives up sensible heat, cools and increases in density. In one specific example, an evaporative cooler may be a useful option for turbine inlet air. With the use of an optional evaporative cooler, adding the water to the turbine inlet air will provide a higher mass flow rate and pressure ratio for the turbine and will cause in an increase in turbine output and efficiency. For example, considering a dry-bulb temperature of 40° C. with 20% relative humidity, the output power may be increased by about 12% if an 80% effective evaporative cooler is used. Correspondingly, the heat rate decreases by about 4%. The benefit of an evaporative cooler system from an economic point of view is related to the potential average annual increase in output from the turbine. Of course, evaporative coolers may be used in other example environments.
In general, within an evaporative cooler a spray system wets media the medium and the water flows through the media (e.g., corrugated layers of fibrous material). Air flow intermixes with the flowing water at the media. The water flows down through the media by gravity and non-evaporated water is collected within a drain pan. In turn the drain pan is connected to a sump which collects water for recirculation/reuse to the media.
It is to be appreciated that the presence of water within the evaporative cooler makes the environment within the evaporative cooler somewhat adverse. The use of materials that are adversely affected by water should be avoided. One example material that is typically used within an evaporative cooler is stainless steel. One drawback of stainless steel is a relatively high cost of material. Continued efficient operation of the evaporative cooler is a typical desired expectation. As such there is a need for a successive generation of evaporative coolers that provide improvements.